DB2: 解除被锁定的表
某日无法查询DB2的数据库的某一张表，执行查询语句的后返回死锁或超时的错误:
SQL0911N The current transaction has been rolled back because of a deadlock
or timeout. Reason code "68". SQLSTATE=40001’
其他的表实行数据库没有什么问题，只有一张或几张表出现这个问题，造成这个原因一般是由于表被锁造成的，也可以使用查看DB2数据库的建康状态来确认，处理方法见以下步骤。
步骤一：使用命令get snapshot来查询哪些进程锁了哪些表。命令如下：
db2 get snapshot for locks on databasename
db2inst1@HOST1:~> db2 get snapshot for locks on mydb
Database Lock Snapshot
Database name = MYDB
Database path = /home/db2data/db2inst1/NODE0000/SQL00001/
Input database alias = MYDB
Locks held = 20
Applications currently connected = 21
Agents currently waiting on locks = 0
Snapshot timestamp = 04/16/2009 14:59:29.185370
…………………………
…………………………
Application handle = 838
Application ID = GA47AA28.D60B.0154C5152621
Sequence number = 1432
Application name = javaw.exe
CONNECT Authorization ID = DB2INST1
Application status = UOW Waiting
Status change time = Not Collected
Application code page = 1208
Locks held = 0
Total wait time (ms) = Not Collected
Application handle = 1076
Application ID = GA47AA28.GF12.0194C4113924
Sequence number = 0001
Application name = javaw.exe
CONNECT Authorization ID = DB2INST1
Application status = UOW Waiting
Status change time = Not Collected
Application code page = 1208
Locks held = 8
Total wait time (ms) = Not Collected
List Of Locks ＃在application handle紧跟后面出现list of locks表明该application handle锁了表或对象
Lock Name = 0x030039020DFF11000000000052
Lock Attributes = 0x00000000
Release Flags = 0x00000004
Lock Count = 1
Hold Count = 0
Lock Object Name = 1163533 ＃被锁对象名称
Object Type = Row ＃被锁对象类型
Tablespace Name = tbs_data ＃被锁对象所在的表空间
Table Schema = DB2INST1
Table Name = t_mytable1 ＃被锁的表名
Mode = X
Lock Name = 0xFF000000010000000100120056
Lock Attributes = 0x00000000
Release Flags = 0x40000000
Lock Count = 2
Hold Count = 0
Lock Object Name = 0
Object Type = Internal Variation Lock
Mode = S
Lock Name = 0x0300390200FF11000000000052
Lock Attributes = 0x00000000
Release Flags = 0x00000002
Lock Count = 1
Hold Count = 0
Lock Object Name = 1163520
Object Type = Row
Tablespace Name = tbs_data
Table Schema = DB2INST1
Table Name = t_mytable2
Mode = X
…………………………………………………………………………………
步骤二：使用命令force来断开这些进行了死锁的进程来。命令如下：
db2 "force application (handle id)"
db2inst1@HOST1:~>db2 "force application (838)"
DB20000I The FORCE APPLICATION command completed successfully.
DB21024I This command is asynchronous and may not be effective immediately.
db2inst1@HOST1:~>db2 "force application (1076)"
DB20000I The FORCE APPLICATION command completed successfully.
DB21024I This command is asynchronous and may not be effective immediately.
步骤三： 使用命令list application查看是否已经断开了哪些进行了死锁的进程。命令如下：
db2inst1@HOST1:~> db2 list applications
Auth Id Application Appl. Application Id DB # of
Name Handle Name Agents
-------- -------------- ---------- ------------------------------ -------- -----
DB2INST1 db2bp 1330 *LOCAL.db2inst1.090416134941 MYDB 1
DB2INST1 db2jccThread-8 85 GAB40153.G869.0120AF1F5A2E MYDB 1
DB2INST1 db2bp.exe 63 GA47AA28.BA0C.018346132405 MYDB 1
DB2INST1 db2bp 825 *LOCAL.db2inst1.090416103954 MYDB 1
DB2INST1 javaw.exe 1039 GA47AA28.F411.0194C4113304 MYDB 1
DB2INST1 db2bp.exe 928 GA47AA28.L710.015844102651 MYDB 1
DB2INST1 dbdaemon 877 *LOCAL.db2inst1.090408150559 MYDB 1